The suffix -dom attaches to the end of words to create nouns meaning “the state of being” something or “the world of” something. When you add -dom to a word, you're describing either a condition or a realm.

For states of being, think about freedom: the state of being free. Wisdom means the state of being wise. Boredom is the state of being bored. Notice how -dom transforms descriptive words into concrete conditions you can experience.

For realms or territories, consider kingdom: the realm ruled by a king. Christendom historically referred to all the Christian lands. Even stardom describes the world that celebrities inhabit, separated from ordinary life by their fame.